Variable cut-off valve fob steam-engines



. UNTTED sTATEs PATENT i onnion.

I. M. COLMAN, OF MILWAUKEE, VISGONSIN.

VARIABLE CUT-OFF VALVE FOR STEAM-ENGINES.

Specification of Letters Patent No. 23,553, dated April 12, 1859.

T o all whom it may concern:

Be it known that I, I. M. CoLMAN, of the city of Milwaukee, in the State of VVisconsin, have invented a new useful Improvement on Variable Cut-fii`s for Steam- Engines; and I do hereby declare that the following is a full, clear, and exact descrip tion of the same, reference being had to the accompanying drawings and to the letters and marks thereon.

My invention consists in so' combining with the ordinary slide valve the doubleseated balanced or equilibrium valve as to have it act as a drop-valve cut-off, variable in its action7 and deriving its motions from the movements of the. slide-valve.

Of the drawings forming part of this specification Figure l is a longitudinal section of a valve chest with the cut-ofil and slide valve as attached to a horizontal cylinder, and Q- a like section of the same as attached-to a vertical cylinder.

In both of these figures like letters and marks indicate like parts.

(a, a) mark the usual induction or steam ports at theends of the cylinder and (b, 2)) the eduction or exhaust ports. y (c, c) mark the slide valves and (d) the stem, which may pass through the passage in the one valve as shown by the drawing Fig. l. or may be attached to the ends of the valves.

(c, c) mark the passages for the steam through the slide valves, (f, the balanced or equilibrium valves, (gf, g) their seats and (7L, le) their stems. y

(i, ai) mark angular forked levers, the forks embracing the drop-valve stems represented in l, and the upper ends of the levers pointing toward the toes (j, j) pro jecting downward from the top of the valve chest. These toes are jointed to the lower ends of rods (71:, 7c) which pass through stuffing boxes and at their upper ends are embraced by levers (Z, l), which are the adjusting levers, their inner ends being affixed to an adjusting nut (m) on the standard (nl when the adjustment is to be made by hand, or to the stem of the governor when it is designed to have the governor regulate the tripping` of the drop-valves.

In Fig. 2 the levers for operating the having its fulcrum between the stem of the valve and the toe (yw) g and it will be seen that the lower toe (yw) is rigid, the end of the lever' (ya) being hinged instead of being rigid as in the other levers. This change in the form of the levers and the condition of the toes is such as to adapt the invention to the vertical cylinder and to allow of the adjustab'ility of the toes by hand or by the governor, as with the arrangement for the horizontal engine.

It is evident that my invention is as susceptible of being applied to the single or short slide valve as to the double or long slide represented by the drawings. When applied to the short or single slide, only one drop or equilibrium valve will be used, but the two angular levers willbe attached, the one for lifting the drop valve for the one end and the other for the other end of the cylinder. Upon motion being given to the usual eccentric on the main shaft and communicated to the slide valve by its'rod the movement of the slide valves brings the levers of the drop valves in contact with the toes lifting the valves from their seats on the one movement and moving the toe on its hinge on the other movement and thus admitting the steam or not as required, and the valve being kept from its scat as the toe may be projected more or less within the steam chest. Under this combination all the advantages of the drop valves cut-off will be derived with perfect and accurate adjustability either by hand or by the gov ernor.

What I claim as my invention and desire to secure by Letters Patent is- Combining the double seated balanced or equilibrium valve with the ordinary slide valve of steam engines as herein set forth.

I. M. COLMAN.

GEO. R. SMITH. 

